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• 1 Introduction
• 2 Hull design approach
• 3 Results
• 4 Discussion & References

4 Discussion & References

Discussion

Designing a waterbike that performs well at high-speed during a 100 meters sprint, a long distance of 10 kilometres is quite a challenge. Not a single hull configuration performs best for both distances and a multiplicity of design constraints and uncertainties of theoretical models result in multiple iterations and attempts.
The propulsion power is limited to the leg power of the sportsmen that are pushing the pedals. Besides that, all energy losses result into reduction of speed. And because the torque that occurs in the propulsion shaft can sometimes be larger than in a car, a reliable structural design of the propulsion unit with low friction is inevitable.

Transferring the human energy towards the hull energy includes energy losses. Underestimating these losses is one of the main reasons why waterbike designs do not perform as expected. Other causes are: Exceeding of the total waterbike design weight, excessive backward trim of the hull at high sailing speeds and poor ergonomics due to excessive laying position backward.

Looking at the diversity of conceptual designs of waterbikes it is shown that there is not a single concept that performs best overall. It is always a combination of design choices that make the difference.

References

[1] Ir. J.Pinkster,"MT113, Ship Design IV", University of Delft, 1994

[2] Ir. Raven, "User guide CATRES", version 3 report no X.47142-2-RF, MARIN Wageningen, Oktober 1988

[4] Different authors DWT, "Flying Delft Blue", internal technical report about development of hydrofoil "Flying Colours", Delft Waterbike Technology (DWT), The Netherlands, 1991

[3] Different authors DWT, "Het project Nederwood", internal technical report about development of planing hull Nederwood, Delft Waterbike Technology (DWT), The Netherlands, July 1996

[4] Different authors DWT, "Page", Internal technical report about development of slender mono-hull "Macbath", Delft Waterbike Technology (DWT), The Netherlands, July 1997

[5] Walree, F. van, Resistance Prediction Method for Hydrofoil Craft, Laboratorium van scheepsbouwkunde TH Delft, rapport no. 690-S 1985

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